I have the same error message. I am running a batch file that calls a SQL file that runs a pretty simple update script. When I run the script manually, it runs fine. The same syntax that applies to the call to this script is used to call multiple other scripts on a nightly basis, and the others all work. Here is the error message (which I know is not very helpful by itself):

Incorrect syntax near 'ÿ'.

Like I said, the same batch file contains calls to 6 SQL scripts, all with the same credentials and syntax.

Are you actually getting the lowercase y with the two little dots over it?

If so, your sql file is saved in Unicode, not standard ASCII. Open the sql file in SSMS, click file ~ save as, and then on the Save button click the little down-arrow at the right - select "save with encoding" and then select 1252 and then you can save it in ASCII.